Roll screen assemblies are well known in the art. The assignee of this invention, c.o.b. as Preferred Engineering Limited, has several patents issued in relation to various embodiments of roll screen products. Other roll screen products are discussed in those particular issued patents, the details of which patents are incorporated by reference in this application with respect to typical roll screen assemblies and further the prior art discussed therein.
The problem being addressed with respect to the present application is the weakness of typical center locking devices for roll screen assemblies as best seen in relation to FIGS. 10 and 10A. By providing a lock L1 located on the end of the roll out screen and the jamb of a patio door assembly locking the screen at that location creates a predetermined amount of slack in the screen adjacent the high and low ends of the screen as illustrated. However, by providing a latch release bolt proximate the header and sill as shown as 30a and 30b in FIG. 10A, the slack in the screen disappears and the forces on entire screen are more uniformly distributed. Further the bowing on the roll tube and the handle is minimized. As discussed the slack created in the screen cloth by latching typically at a center point at L1 results in the screen cloth coming out the track with continual cycling of for example a patio screen.
The typical screen assembly mounted on a tube R accumulates around said tube loaded by a spring and mounted on brackets as shown. However, the strength of the tube spring will engage through the point L1 and will therefore create effectively a triangular stretch in the screen cloth as the tube bows in typically approximately 2 mm.
However, by providing a locking portion 30a and 30b as will be described herein after in the sill and the header or alternatively the jambs for the track within which the screen cloth rides, the entire screen cloth will be stretched by the strength of the tube spring and this will result in the motion of the screen to and from its roll out position within the track without as many problems occurring.
Aside from the prior art of Preferred Engineering, the details of which were incorporated by reference into this application with respect to roll out screen assemblies, one particular centre locking device for a window assembly of Preferred Engineering is found in the art, namely CA 2,086,132 a centre lock as best seen therein in relation to FIG. 32 and 33 for a window assembly. However, such an assembly would not be appropriate for use with a roll screen.
Applicant is also aware of U.S. Pat. No. 4,639,021 to Hope for use with a door as best seen therein in relation to FIG. 1. However, this mechanism is complicated and involves a lot of hardware and meant for use with a door.
Nowhere within the prior art to applicant's knowledge is their found a simple latch mechanism for use with a screen assembly and preferably a roll screen assembly which provides for the engagement of either cut outs in the track or blocks in the track to latch the screen assembly at a fully paid out position in the header and sill or alternatively the jamb tracks.
It is therefore a primary object of the invention to provide a simple latch assembly engageable with sill and header or jamb track parts for a screen assembly.
It is a further object of the invention to provide such an assembly which is simple and light weight but obviates the complications of the previously known center lock devices in prior art constructions.
It is yet a further object of the invention to provide an actuator for a latch assembly which includes cam surfaces to engage detents to operate said latch assembly and preferably to operate a detent engaged with an operator for the header or jamb latching portion and a detent for an operator for engaging the sill or jamb latching portion.
Further and other objects of the invention will become apparent to one skilled in the art when considering the following summary of the invention and the more detailed description of the preferred embodiments illustrated herein.